Furnace



June 27, 1933. J PETERSON 1,915,949

FURNAC E Filed Dec. 1, 1931 g 1 INVENTOR.

Fwedozf J fite son ATTORNEY.

Patented June 27, 1933 PATENT OFFICE FBEDOLF J. PETERSON,

OF DETROIT, MICHIGAN FURNACE Application filed December My invention relates to heat treating furnaces and particularly to furnaces for carbonizing metallic articles. More part1cularly my invention is related to a furnace 1n 5 which the work is progressively moved through the furnace in the presenceof a carbonizing gas generated in an auxillary furnace and conducted to the work and circulated in proximity thereto in a manner calculated to produce a product of uniform qual- An object of my present invention is to facilitate the carbonizing of articles by providing a furnace structure adapted for progressively carbonizin the work relatively quicker and more uni ormly than is possible with individual carbonizing retorts.

A further object of my invention is to provide a heat treating furnace structure 1n which case hardened articles may be produced of substantial uniform quality at a minimum of expense.

Other features and objects of my invention will be made more apparent as the description progresses in which like characters refer to like parts in the accompanylng drawing illustrating a preferred embodiment of my invention, and in which:

Fig. 1 is a vertical sectional view of a furnaoe constructed in accordance with my 1nvention,

Fig. 2 is a cross-sectional view taken substantially on the line 22 of Fig. 1, and

Fig. 3 is a detail view of one of the work containers or cradles.

In the illustrated embodiment of my invention I have provided for purposes of illustration a furnace structure A which in general is constructed of fire clay or other suitable heat resisting material and which encloses a retort B of a heat resisting metal or alloy. The furnace structureA is preferably constructed in such a manner as to permit the work to be stacked therein, and in general provides a loading zone C, a heat treating zone D and an unloading zone E.

The work to be heat treated or carbonized is preferably stored in a plurality of containers or cradles F, which are preferably adapted to be stacked in the furnace (see Fig.

1). The retort, constructed of suitable heat resisting material and open at both ends preferably extends from adjacent the bottom of the furnace to the top, one end of the retort being closed by the door 10, While the other end, the top, is closed by a removable cover 11. The retort B enclosed within the furnaoe structure is spaced from the walls there of and heating devices, such as electrical heating units 12 are suitably located and supported in said space surrounding the retort.

The present construction is preferably arranged to permit the progressive movement of the work through the retort. In the illus trated embodiment, it will be evident that the Work may be passed through from the top to the bottom or from the bottom .to the top-as desired. The heat treating or carbonizing gas is preferably produced from a material which generates a carbonizing gas when subjected to heat. Thus I preferably employ an auxiliary furnace A constructed to support a retort 20 in which the gas producing material 21 is contained, the retort being heated by any suitable means such as electrical heating units 22. The material may be introduced into the retort 20 through the chute or other suitable filling device 23. The gas generated therein may be conducted to the Serial No. 578,343.

v retort B through the pipe 24, the flow of gas being preferably regulated by a suitable con- 1 trol valve 25. I preferably introduce the gas into the retort B at a point adjacent to the bottom thereof so as to facilitate the circulation of the gas through the same, said retort having an outlet 26 and associated valve 26' suitably located so as to exhaust the gas after the same has been circulated longitudinally through said vertical retort.

The work is moved longitudinally through the retort under the influence of a ram or plunger 30 which may be hydraulically operated if so desired. The plunger is provided with a head 31 having a circumferential groove 32 about the peripheral edge adapted to engage a downturned flange 33 around the inside wall of the retort so as to seal the main portion of the retort from the delivgry chamber E when the plunger is raise I do not desire to support the stack of cradles F solely by the plunger 30, and have provided a plurality of retractable supports or brackets 34 adapted to be moved into engagement with the lowermost cradle, said supports engaging the downwardly and inwardly extending tapered portion F1 of the cradle. These sup orts are preferably slidably supported by t e furnace structure and may be moved by means of rods 35. One manner in which the work can be progressively moved through the retort is to progressively lower the stack of work-containers or cradles. The supports 34 are thus first retracted and the plunger 1s lowered until the lowermost cradle is aligned with the laterally extending delivery chamber E. Any suitable means may be employed to remove the lowered cradle, through the opened door 10 but prior to removing same the supports 34 are projected and engaged with the cradle immediately thereabove to support the .remainin cradles.

Prevlously to lowering the stack of cradles an additional cradle is preferably introduced at the top, the same being normally supported bythe retractable supports or brackets 36 or similar construction as brackets 34 and similarly actuated. -On lowering the stack of cradles the supports 36'are retracted to permit the most recently added cradle to follow the others into the heat treating zone D. The supports 36 may then be again projected and another cradle loaded with work to be heat treated placed therein, after WlllCll the cover 11 may be again set in place.

Obviously, the above operation can be readily reversed and the work passed from chamber E to C if so desired.

Thus it will be seen that the work is progressively moved through the heat treating retort in the presence of a heat treating or carbonizing gas. The length of time each cradle is in the retort depends on the length of the furnace and the time interval between each cradle removal. It will be obvious that was a very uniform heattreatment can be produced, resulting in articles of uniform quality and strength as desired.

The cradle or container F is preferably provided with a frusto-conical base F1 and a removable frusto-conical cover F2 adapted to seat on an annular seat 40 carried by the body portion F--3. The cover preferably supports another cradle when 1n the furnace retort, the frusto-conical base and cover being preferably perforated as at 41 and 42 respectively to permit the gas circulate through the interior thereof, the sides of the body portion F3 being also perforated or formed of lattice work.

I find that a system such as shown in the accompanying drawing illustrating a preferred embodiment of my invention is very economically constructed and operated. Fur-- thermore the same maybe very readily and easily controlled and rovides a furnace in which various types 0 work can be quickly and uniformly carbonized or case hardened with a minimum of expense and labor and with a minimum of waste.

Although I have illustrated but one form of my invention and have described in detail but a single application thereof, it will be apparent to those skilled in the art to which my inventionpertains that various modifications and changes may be made therein without departing from the spirit of my invention or from the scope of the appended claims.

I claim:

1. In a device of the character describedincluding a pair of associated furnace structures each having a retort, means for heating said retorts, means interconnecting said retorts including gas conductin means for transferring carbonizing gas rom one retort to the other, said retorts being otherwise closed, one of said retorts having removable closure members and constructed to support work to be carbonized and the other constructed for supporting a material producing carbonizing gas when subjected to heat.

2. In a device of the character described including a pair of associated furnace struc-' tures each having a retort, means for heating said retort, means interconnecting said retorts mcludinggas conducting means for continuously transferring carbonizing gas from one retort to the other, said retorts being otherwise closed, one of said retorts constructed to provide means movably supportmg work to be carbonized and the other constructed for supporting a material producing.

carbonizing gas when subjected to heat.

3. In a device of the character described including a pair of associated furnace structures each having a retort, means for heat ing said retorts, means permanently interconnecting said retorts including 'gas conducting means for transferring carbonizing gas from one retort to the other, said retorts being otherwise closed, one of said retorts constructed for supporting a material producing carbonizing gas when subjected to heat, and means associated with said other .retort for progressively moving the work III work, and means associated with said other retort for progressivel moving said work containers through sai retort.

5. In a device of the character described including apair of associated furnace structures each having a retort, means for heating said retorts, means interconnecting said retorts including gas conductin means for transferring carbonizing gas tort to the other, said retorts being otherwise closed, one of said retorts constructed for supporting a material producing carbonizing gas when subjected to heat, a pluom one re-' rality of containers for supporting the work, 

